Q: does Moode needs to index the music library?

[the_bertrum]

However can I use any app, like BubbleUPnP to access my library (without local indexing), to stream music to the Allo Boss 2 using Moode? I used BUPnP as an example as this is what I am using at the moment for all players (Wi-Fi, BT, ethernet) visible on my LAN. 

I'm not sure I've understood what you want properly, but I think the answer is yes!
If you can see your library from the Synology music server in your libraries in BubbleUPnP, then you can turn on the UPnP renderer in moOde and select that as a renderer in BubbleUPnP and send music to it. No need for a local index of the files on moOde. I find setting the UPnP type in moOde to "OpenHome" works best.